#include <stdio.h>
void shift(char *, int *);
void Add(int *, int *, int *);
#define MAX 504



char cha[MAX] = {0}, chb[MAX] = {0};





int a[MAX] = {0}, b[MAX] = {0}, c[MAX] = {0}, i = 0, j;

int main(void) {
	scanf("%s", cha);
	scanf("%s", chb);
	shift(cha, a);
	shift(chb, b);
	for (j = MAX - 1; j >= 0; j--) {
		if (a[j] != -b[j]) {
			break;
		}
	}
	if (j < 0) {
		printf("0");
		return 0;
	}
	Add(a, b, c);
	if (c[1] == 9) {
		i++;
		while (c[i] == 9) {
			i++;
		}
		printf("-");
		for (i; i < MAX - 1; i++) {
			printf("%d", 9 - c[i]);
		}
		printf("%d", 10 - c[i]);
	} else {
		while (c[i] == 0) {
			i++;
		}
		for (i; i < MAX; i++) {
			printf("%d", c[i]);
		}
	}
	return 0;
}

void shift(char *cha, int *a) {
	int i = MAX - 1, j = MAX - 1;
	if (cha[0] != '-') {
		while (cha[i] == 0) {
			i--;
		}
		for (i; i >= 0; i--) {
			a[j] = cha[i] - '0';
			j--;
		}
	} else {
		while (cha[i] == 0) {
			i--;
		}
		for (i; i > 0; i--) {
			a[j] = cha[i] - '0';
			a[j] = -a[j];
			j--;
		}
		cha[0] = 0;
	}

	return;
}

void Add(int *a, int *b, int *c) {
	int i;
	for (i = MAX - 1; i > 0; i--) {
		c[i] += a[i] + b[i];
		if (c[i] > 9) {
			c[i] -= 10;
			c[i - 1]++;
		} else if (c[i] < 0) {
			c[i] += 10;
			c[i - 1]--;
		}
	}
	return;
}
/*
讲真的，我现在再来看这个程序我都佩服我自己，我当时真牛逼，写的程序现在看还是那么
牛逼，这个高精加法，不仅是高精加法，也是高精减法
*/